The invention relates to an electric power tool, especially to a hand-held circular saw, routing machine and the like, having a circular tool that is motor-driven by means of a shaft, whereby the tool can be clamped to the shaft by means of a clamping device that can be actuated by a clamping lever; having a mechanical braking device that, when activated, brakes the tool; a switching element to turn the motor ON and OFF; and a safety element which, when in a safety position, prevents the motor from being turned on and activates the braking device and which, when in a release position, allows the motor to be turned on and releases the braking device, whereby the braking device is mechanically connected to the safety element.
Electric power tools, especially hand-held circular saws of the type described above, use safety devices in order to prevent a user from improperly handling the hand-held circular saw. Especially electric power tools with circular tools such as, for example, hand-held circular saws, have such safety devices. When a motor is turned off by a switching element, a braking device brakes the tool, thereby preventing said tool from continuing to rotate without control. In this state, a safety element is in its safety position, thus preventing the motor from being turned on again by the switching element. In order to once again drive the tool with the motor, the user first actuates the safety element, which releases the braking device through a mechanical connection. Only in this release position of the safety element is the user able to turn on the motor by actuating the switching element so as to drive the tool via a shaft. In order to adapt the rotational speed of the tool to the motor, a gear can be installed, for example, between the motor and the tool.
Such an electric power tool is known, for example, from EP B1 444,909, with a motor-driven circular tool that can be clamped by means of a clamping device onto a shaft that is connected to the motor. In order to brake the tool, the electric power tool has a mechanical braking device that is mechanically connected to a safety element. The safety element has a safety position in which it is not possible to turn on the motor and in which the braking device is activated. In the release position, the motor can be turned on and the braking device is released.
A drawback of the known device is that the rotating tool can still be uncoupled. Especially in order to save time, the user may be tempted, for example, to operate the clamping device while the tool is still rotating or while the electric power tool is switched on. This drawback exists especially in the case of tool-free clamping devices, and, for example, which components of the electric power tool can be damaged.